The Distribution of Arsenic Compounds in the Ocean: Biological Activity in the Surface Zone and Removal Processes in the Deep Zone

The gel phase of articular cartilage is reinforced by collagen fibrils. These fibrils have low flexural and torsional stiffness, but are able to provide reinforcement if deformation of the tissue increases their tensile stress. An estimate suggests that the lengths of collagen fibrils in articular cartilage are at least of the same order as their critical length so that tensile stress in the tissue will increase the stress in the fibrils rather than simply pull them out of the gel. In the surface zone the collagen fibrils are oriented so that the efficiency of reinforcement, η, is about 0.6 tangential to the surface; tension in the fibrils is thus able to withstand swelling pressure within the tissue whose condition for stability resembles that of a pressure vessel. Swelling pressure allows the tissue to support applied pressure. An intermediate zone has a roughly isotropic η value of about 0.2, while in the deep zone collagen fibrils appear to tie the cartilage to the subchondral bone; in this deep zone η has a value of about 0.6 perpendicular to the surface direction. There is also some preferred orientation of collagen fibrils in the plane of the articular surface within the surface zone; in patellar cartilage the preferred orientations can be related to the direction of stress which could be generated by movement of the joint.

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The structure and reactivity of arsenic compounds: Biological activity and drug design

Structure and Bonding - Bioinorganic Chemistry ◽

10.1007/3-540-54261-2_3 ◽

1991 ◽

pp. 129-190 ◽

Cited By ~ 44

Author(s):

Orla M. Ni Dhubhghaill ◽

Peter J. Sadler

Keyword(s):

Biological Activity ◽

Drug Design ◽

Arsenic Compounds

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Biosensors for nitrogen control in wastewaters

Water Science & Technology ◽

10.2166/wst.1996.0374 ◽

1996 ◽

Vol 34 (1-2) ◽

pp. 213-220 ◽

Cited By ~ 7

Author(s):

A. G. Massone ◽

K. Gernaey ◽

H. Bogaert ◽

A. Vanderhasselt ◽

A. Rozzi ◽

...

Keyword(s):

Wastewater Treatment ◽

Biological Activity ◽

Carbon Source ◽

Wastewater Treatment Plants ◽

Nitrogen Control ◽

Biomass Activity ◽

On Line ◽

Removal Processes ◽

Nitrate And Nitrite ◽

Activated Sludge Systems

The control of nitrogen removal processes in activated sludge systems requires not only on-line values of the parameters such as ammonium, nitrate and nitrite, but also an evaluation on the nitrifying and denitrifying biomass activity, influent toxicity and carbon source requirements for denitrification. This paper describes four different biosensors, two on denitrification and two on nitrification. They all measure the biological activity of the nitrifying or denitrifying bacteria. Three of them measure nitrogen and carbon species, the fourth biosensor measures influent toxicity. These instruments open new perspectives for efficient on-line monitoring of wastewater treatment plants.

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Virus-Like Particles in a Human Breast Cancer: Structural Similarity to Previously Reported Particles

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100072332 ◽

1973 ◽

Vol 31 ◽

pp. 378-379

Author(s):

G. Kasnic ◽

S. E. Stewart ◽

C. Urbanski

Keyword(s):

Breast Cancer ◽

Biological Activity ◽

Human Breast Cancer ◽

Osteogenic Sarcoma ◽

Human Tumor ◽

Structural Similarity ◽

Cell Tumor ◽

Human Breast ◽

Human Tumor Cell ◽

Type Particle

We have reported the maturation of an intracisternal A-type particle in murine plasma cell tumor cultures and three human tumor cell cultures (rhabdomyosarcoma, lung adenocarcinoma, and osteogenic sarcoma) after IUDR-DMSO activation. In all of these studies the A-type particle seems to develop into a form with an electron dense nucleoid, presumably mature, which is also intracisternal. A similar intracisternal A-type particle has been described in leukemic guinea pigs. Although no biological activity has yet been demonstrated for these particles, on morphologic grounds, and by the manner in which they develop within the cell, they may represent members of the same family of viruses.

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Effects of Vincristine on Endothelial Microtubules in the Spinal Cord

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100090270 ◽

1976 ◽

Vol 34 ◽

pp. 58-59

Author(s):

John L. Beggs ◽

John D. Waggener ◽

Wanda Miller

Keyword(s):

Spinal Cord ◽

Biological Activity ◽

Horseradish Peroxidase ◽

Transport Mechanism ◽

Vasogenic Edema ◽

Vesicular Transport ◽

Close Proximity

Microtubules (MT) are versatile organelles participating in a wide variety of biological activity. MT involvement in the movement and transport of cytoplasmic components has been well documented. In the course of our study on trauma-induced vasogenic edema in the spinal cord we have concluded that endothelial vesicles contribute to the edema process. Using horseradish peroxidase as a vascular tracer, labeled endothelial vesicles were present in all situations expected if a vesicular transport mechanism was in operation. Frequently,labeled vesicles coalesced to form channels that appeared to traverse the endothelium. The presence of MT in close proximity to labeled vesicles sugg ested that MT may play a role in vesicular activity.

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Stannous fluoride treatment of acid-etched caries-like lesions of enamel: A scanning electron microscopic study

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100113482 ◽

1984 ◽

Vol 42 ◽

pp. 720-721

Author(s):

M. John Hicks ◽

Leon M. Silverstone ◽

David G. Gantt ◽

Catherine M. Flaitz

Keyword(s):

Acid Etching ◽

Surface Zone ◽

Electron Microscopic ◽

Fluoride Treatment ◽

Stannous Fluoride ◽

Scanning Electron Microscopic Study ◽

Demineralized Enamel ◽

Intact Surface ◽

Topical Fluoride

Although fluoride levels become elevated in sound enamel following a topical fluoride treatment, the caries-preventive effect of fluoride is thought to be due primarily to the role of fluoride in remineralization of clinically undetectable enamel lesions and hypomineralized enamel. During lesion formation, redistribution of fluoride from the enamel surface to the subsurface demineralized enamel occurs. This results in a surface zone with a relatively low fluoride content. In order to maintain an intact surface zone over a carious lesion, it may be necessary to replenish the fluoride levels with an exogenous fluoride source. By acid-etching the lesion surface, a more reactive surface is made available for fluoride interaction. In addition, porosities and etching patterns may be created, allowing for bonding of a caries-resistant resin material to the lesion surface. The purpose of this study was to determine the integrity of the caries-like lesion surface following acid-etching and subsequent stannous fluoride treatment (SnF2).

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